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This outbreak appears to be over. Listeria monocytogenes infection (listeriosis) is an important cause of illness in the United States. More information about listeriosis, and steps people can take to reduce their risk of infection, can be found on the CDC Listeria Web Page.

Clinical Features/Signs and Symptoms

Listeriosis is a life-threatening infection caused by eating food contaminated with the bacterium Listeria monocytogenes. The disease primarily affects pregnant women, persons with weakened immune systems, and older adults. Rarely, persons without these risk factors can be affected.

A person with listeriosis usually has fever and muscle aches, often preceded by diarrhea or other gastrointestinal symptoms. Almost everyone who is diagnosed with listeriosis has invasive infection (meaning that the bacteria spread from their intestines to the bloodstream or other body sites).

Listeriosis is treated with antibiotics. Persons in a higher-risk category, including pregnant women, persons with weakened immune systems, and older adults, who experience symptoms within 2 months after eating contaminated food should seek medical care and tell the physician or health care provider about eating the contaminated food.

Pregnant women: Pregnant women typically experience only a mild, flu-like illness. However, infection during pregnancy can lead to miscarriage, stillbirth, premature delivery, or life-threatening infection of the newborn.

Healthy persons. Healthy persons occasionally develop invasive listeriosis. In addition, persons exposed to a very large dose of Listeria bacteria can develop a non-invasive illness with diarrhea and fever (meaning that the bacteria do not spread into their blood stream or other sites).

If a person has eaten food contaminated with Listeria and does not have any symptoms, most experts believe that no tests or treatment are needed, even for persons at higher risk for listeriosis.